Objective-C - Programmer Sheet

Built-In Types

Type	Description	Size
char	A character	1 byte
int	An integer — a whole number	4 bytes
float	Single precision floating point number	4 bytes
Double	Double precision floating point number	8 bytes
short	A short integer	2 bytes
long	A double short	4 bytes
long long	A double long	8 byte
BOOL	Boolean (signed char)	1 byte

Enumeration types

enum  typeName { identifier1, ... identifiern};

typedef

typedef  typeName  identifier;

Constants

const type  identifier  = value;
#define identifier value

Arithmetic Operators

Operator	What It Does
+	Addition
-	Subtraction
*	Multiplication
/	Division
%	Modulo

Relational and Equality Operators

Operator	What It Does
==	Equal to
!=	Not equal to
>	Greater than
<	Less than
>=	Greater than or equal to
<=	Less than or equal to

Logical Operators

Operator	What It Does
!	NOT
&&	Logical AND
\|\|	Logical OR

Compound Assignment Operators

Operator	What It Does
+=	Addition
-=	Subtraction
*=	Multiplication
/=	Division
%=	Modulo
&=	Bitwise AND
\|=	Bitwise Inclusive OR
^=	Exclusive OR
<<=	Shift Left
>>=	Shift Right

Increment and Decrement Operators

Operator	What It Does
++	Addition
—	Subtraction
*=	Multiplication
/=	Division
%=	Modulo
&=	Bitwise AND
\|=	Bitwise Inclusive OR
^=	Exclusive OR
<<=	Shift Left
>>=	Shift Right

Bitwise Operators

Operator	What It Does
&	Bitwise AND
\|	Bitwise Inclusive OR
^	Exclusive OR
~	Unary complement (bit inversion)
<<	Shift Left
>>	Shift Right

Other operators

Operator	What It Does
()	Cast
,	Comma
Sizeof()	Size of
? :	Conditional
&	Address
*	Indirection

Control Statements and Loops in Objective-C

if else

if (condition) {
    statement(s) if the condition is true;
}else {
    statement(s) if the condition is not true;
}

for

for (counter; condition; update counter) {
     statement(s) to execute while the condition is true;
}

for in

for (Type newVariable in expression ) {
     statement(s);
}

or

Type existingVariable ;
for (existingVariable in expression) {
    statement(s);
}

while

while (condition) {
    statement(s) to execute while the condition is true
}

do while

do {
   statement(s) to execute while the condition is true
} while (condition);

Jump statements

return ;

break ;

Leave a loop.

continue;

Skip the rest of the loop and start the next iteration.

goto labelName;
...
labelName:

An absolute jump to another point in the program (don’t use it).

exit();

Terminates your program with an exit code.

Declaring Classes and Sending Messages in Objective-C

Interface

#import "Superclass.h"
@interface  ClassName : Superclass {
    instance variable declarations;
}
method declarations
@property(attributes) instance variable declaration;
–d

Implementation

#import "ClassName.h"
@implementation  ClassName
@synthesize  instance variable ;
method definitions
–d

Message Syntax

[receiver message]

#import

#import “filename.h”

Guarantees that a header file will be included only once.

class=""

class="" ClassName;

Clues the compiler into user defined types.